The present invention relates to an integrated blade lubrication controller for a sawmill such as a portable sawmill having a cutting mechanism for sawing lumber. The integrated blade lubrication controller is linked to the throttle controller, so that lubricant is applied to the saw blade only when the throttle is deployed.
There are several prior inventions for portable sawmills.
U.S. Pat. No. 5,784,941 describes a portable sawmill in which the functions of adjusting a cut and making a cut are divided between two separate devices. The invention discloses a vertical chain saw, ideally operated in an upward direction, which moves horizontally along a track. The device has a throttle actuator, that, in conjunction with a chain, operates the throttle of the chain saw, so that the motor of the chainsaw is at full power when cutting, but returns to idle when not cutting. A cooling system is not disclosed.
U.S. Pat. No. 4,275,632 describes a portable sawmill comprising a U-shaped support or carriage, holding a band saw. When in use, a log is placed between the two guide rails and is supported in place by a jacking mechanism with adjustable shelves. The band saw is in a generally horizontal position (though with one end slightly elevated), and does not adjust in a vertical direction; instead, the log itself is moved up and down using a jacking mechanism. The band saw is equipped with a release mechanism for automatically disengaging the drive between the motor and the saw at the end of a cutting stroke. Though the band saw does not have a throttle mechanism per se, the band saw has a lever which can be latched in position in which an idler pulley engages the belt causing power to be transmitted to the band saw. Once the band saw carriage has passed entirely through the log to be sawed, the latch strikes against a top plate, causing the latch to disengage the lever and stop the band saw through disengagement of an idler pulley with the band saw belt. A cooling system is not disclosed.
U.S. Pat. No. 4,235,140 describes a sawmill having a saw carriage having a vertical slide slidable on a vertical post of the sawmill frame, and adjustable vertically thereof by a cable secured at its upper end to a hook hooked into the top of the post. The lower end of the cable is attached to a reel, rotatable by a manual crank. The sawmill is equipped with a handle having a Bowden-wire control to the throttle of the chain saw, such that the chain saw internal throttle mechanism can be activated and controlled from the handle. A cooling system is not disclosed.
U.S. Pat. No. 3,965,788 describes a saw guide for use with a vertically operated portable chain saw. The saw guide comprises support means for the chain saw, to which the saw is attached. The vertical displacement of the chain saw along the support means is by way of a slidable engagement which can be clamped to a desired height using adjusting clamps. The operator uses the chain saw's built in trigger and internal throttle mechanism to operate the chain saw. A cooling system is not disclosed.
U.S. Pat. No. 3,926,086 describes a portable sawmill that uses a complex pulley system to move the chain saw and supporting platform in a horizontal direction. Vertical displacement of the chain saw relative to the log and sawmill frame is through a pair of transversely-spaced vertically-movable racks having their lower ends operatively connected to the bar of the chain saw, a transverse shaft rotatably mounted on the frame, and a pair of transversely-spaced pinions fastened to the shaft and engaging the tracks. The racks and the attached chain saw is raised or lowered relative to the frame and to the log by rotation of the shaft. The chain saw is disclosed to have a pivotal throttle trigger which may be squeezed to adjust the speed of the operating saw between a relatively slow idle speed and a relatively fast cutting speed. The portable sawmill may also have trigger disengagement means engaging the chain saw throttle trigger and operative to cause the saw to return to an idle speed when the trigger deactivating means strikes an object as the cutting saw exits a log being sawed. The trigger disengagement utilizes a detent mechanism on the chain saw trigger, so that the trigger disengagement further depresses the throttle trigger so that the detent is disengaged, snapping the throttle trigger outwardly to its extended position, and returning the operating saw to its idle speed when the saw exits a log being sawed. A cooling system is not disclosed.
Canadian Patent No. 1,200,180 describes a portable sawmill comprising a frame with a guide rail and a carriage moveable along the guide rail. A band saw is supported by the carriage. The carriage is moveable along the guide rail along two sets of wheels, one engaged with the upper side of the guide rail and the other with the lower side. The patent discloses a single lever control which enables the operator to positively engage or brake the band saw, and also to control the engine throttle. Specifically, a brake, a clutch, and a power speed control are all incorporated into a single lever which is actuated at the end of each cut to stop the band saw blade and to lower or stop power velocity. A cooling system is not disclosed.
U.S. Pat. No. 4,210,049 describes an “x” frame for holding a log, with a chain saw affixed to the frame in cantilever position for cutting logs crosswise. The frame comprises a throttle control means including a fingertip throttle control lever pivoted to the end of a handle, and a corresponding lever pivoted at the base end, the levers being connected by a link and the lever being integral with a horizontal crank element so that its end actuates the chain saw throttle when the lever is actuated. A cooling system is not disclosed.
The LumberLite™ 24 mid-size band sawmill and the Lumbermate 2000 full size portable band sawmill (http://www.norwoodindustries.com) are portable sawmills having two horizontal bases, each with a wheel assembly providing planar horizontal movement and fitted onto a set of rails of a sawmill base, two vertical saw supports extending vertically from the horizontal bases, and a top cross rail connecting the two vertical saw supports. The sawmills have a cable rod extending between the vertical saw supports, with a crank handle. The crank handle rotates the cable rod. The saw head is placed below the cable rod and slidably affixed to the vertical saw supports such that it can move vertically along the two vertical saw supports. A cable extends between the cable rod and the saw head, and reels around the cable rod, lifting or lowering the saw head. The saw head is kept in place using clamps on the saw head affixing it to the vertical saw supports. The saw head is displaced horizontally along the rails by pushing a handle. The handle has a lever which acts as a throttle control; the lever is connected to the saw head throttle through a Bowden cable. Thus, by squeezing the lever towards the handle, the throttle is activated. By releasing the lever (which is biased in an outwards position) the throttle is released. The LumberLite™ can be purchased with a saw blade/band cooling system, which consists of a flexible hose affixed to the saw head carriage in a manner such that, when water is run through the hose, it falls onto the saw blade/band. Thus, an operator would connect the opposing end of the hose to a water supply, such as a water tap, and would turn on the water tap before making each cut. The operator would then turn off the water tap, either after each cut, or when finished utilizing the sawmill.
Many sawmills, including the aforementioned sawmills, work better when the saw blade, saw band, or saw chain (as appropriate) is kept cool. This helps keep the blade pitch-free, improves cutting performance, and extends the life of the blade, band or chain. Thus, many sawmills are retro-fitted, or modified, to have a blade lubrication system. Others are sold pre-equipped with a blade lubrication. Essentially, as discussed above with respect to the LumberLite™, the operator affixes one end of a hose, such as a rubber hose to a location proximal to the saw blade, saw band, or saw chain; the other end of the hose is attached to a water/lubricant supply, such as a container or cold water tap. Before use, the operator turns on a valve on the hose, which, in turn, releases water from the hose and onto the saw blade/band/chain, lubricating the blade/ban/chain. In order to conserve water and minimize a muddy or wet cutting environment, typically, the operator will turn the water off after cutting the log, will re-adjust the sawmill for the next cut, then will turn the water back on before starting the next cut. This adds steps, and time, to the log cutting. The existence of these steps also introduces the opportunity for operator error—the operator may forget to turn the water on, resulting in the blade or band overheating, or forget to turn the water off, resulting in mud or flooding.
There is therefore a need for an improved portable sawmill having a blade lubrication system that automatically activates when the saw is in use, and deactivates when the saw is not in use. Such a blade lubrication system would preferably be simple and reliable.